Proximity-based mobile message delivery

ABSTRACT

Proximity-based mobile message delivery is described. In an embodiment, a first user stores a message intended for a second user on a first mobile terminal, while the first mobile terminal is located remote from a second mobile terminal of the second user. Subsequent to this, the first mobile terminal detects that it is now in proximity with the second mobile terminal, and this triggers the first mobile terminal to transmit the message to the second mobile terminal. In embodiments, authentication of the second mobile terminal can be performed before transmitting the message. In another embodiment, a mobile terminal comprises a short-range wireless transceiver that can detect that a further mobile terminal is in proximity, and trigger the transmission of a pre-stored message to the further mobile terminal.

BACKGROUND

There is a class of messaging between persons that can be summarized asentailing ‘hand-delivery’, in that the person who sends, gives orreceives a message wants to be physically present when a message isreceived. Prior to electronically-mediated communications, this would besatisfied by the persons involved simply delivering and/or receiving themessage in question by hand, thus ensuring the interactional aspect.

The importance of this type of messaging cannot be underestimated.Indeed, this importance even shows itself in common law and everydaylanguage. To ‘shake hands’ over a mutual action is a term that labelsboth an actual act, a shaking of hands, and a contract that can be, invarious ways, legally binding for those whose hands have been shaken.Hand-delivery can also afford less formal benefits. For example, whenmessages are exchanged by hand, benefit can come from the sender or‘giver’ seeing the recipient's reaction to the message.

A feature of electronic messaging systems (such as, for example, email,MMS, SMS, etc.) is that they all assume that promptness and certainty ofdelivery are the primary and often the only aspects of messaging thatare significant for both the sender and receiver. The benefitshand-delivery or the contractual and symbolic value of shaking hands ata point of message exchange, are not provided by such electronicmessaging systems.

The embodiments described below are not limited to implementations whichsolve any or all of the disadvantages of known messaging systems.

SUMMARY

The following presents a simplified summary of the disclosure in orderto provide a basic understanding to the reader. This summary is not anextensive overview of the disclosure and it does not identifykey/critical elements of the invention or delineate the scope of theinvention. Its sole purpose is to present some concepts disclosed hereinin a simplified form as a prelude to the more detailed description thatis presented later.

Proximity-based mobile message delivery is described. In an embodiment,a first user stores a message intended for a second user on a firstmobile terminal, whilst the first mobile terminal is located remote froma second mobile terminal of the second user. Subsequent to this, thefirst mobile terminal detects that it is now in proximity with thesecond mobile terminal, and this triggers the first mobile terminal totransmit the message to the second mobile terminal. In embodiments,authentication of the second mobile terminal can be performed beforetransmitting the message. In another embodiment, a mobile terminalcomprises a short-range wireless transceiver that can detect that afurther mobile terminal is in proximity, and trigger the transmission ofa pre-stored message to the further mobile terminal.

Many of the attendant features will be more readily appreciated as thesame becomes better understood by reference to the following detaileddescription considered in connection with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

The present description will be better understood from the followingdetailed description read in light of the accompanying drawings,wherein:

FIG. 1 illustrates a system for proximity-based mobile message delivery;

FIG. 2 illustrates a process for delivering a message based onproximity;

FIG. 3 illustrates an authentication process;

FIG. 4 illustrates an alternative system for proximity-based mobilemessage delivery; and

FIG. 5 illustrates an exemplary computing-based device in whichembodiments of proximity-based mobile message delivery can beimplemented.

Like reference numerals are used to designate like parts in theaccompanying drawings.

DETAILED DESCRIPTION

The detailed description provided below in connection with the appendeddrawings is intended as a description of the present examples and is notintended to represent the only forms in which the present example may beconstructed or utilized. The description sets forth the functions of theexample and the sequence of steps for constructing and operating theexample. However, the same or equivalent functions and sequences may beaccomplished by different examples.

Although the present examples are described and illustrated herein asbeing implemented in a mobile messaging system, the system described isprovided as an example and not a limitation. As those skilled in the artwill appreciate, the present examples are suitable for application in avariety of different types of other communication systems.

Reference is first made to FIG. 1, which illustrates system forproximity-based mobile message delivery. The system in FIG. 1 enables amobile terminal to act as a proxy for a person operating the mobileterminal, such that electronic ‘hand-delivery’ of a message can beperformed. FIG. 1 illustrates a first user 100 having a first mobileterminal 101, and a second user 102 having a second mobile terminal 103.In the example shown in FIG. 1, the first user 100 wants to deliver amessage to the second user 102 using the hand-delivery mechanism.

FIG. 1 also shows a detailed view of the mobile terminals. The firstmobile terminal 101 comprises a transceiver 104, which is arranged totransmit and receive wireless signals. Preferably, the transceiver 104is a short-range wireless transceiver, for example of the type used toestablish and operate a personal area network (PAN). An example of sucha short-range wireless transceiver is a Bluetooth® transceiver. In otherexamples, different types of short-range wireless transceivers can beused, such as ultra-wideband (UWB), near-field communication (NFC), orZigBee transceivers, or any other transceiver suitable for wirelesslytransmitting and receiving data between mobile terminals over shortdistances.

Preferably, the transceiver 104 comprises a hardware identity 105assigned to the transceiver 104 (labeled HW_1 indicating the hardwareaddress for the first mobile terminal 101), such as a media accesscontrol (MAC) address. The transceiver 104 sends and receives signalsvia an antenna 106.

The mobile terminal 101 also comprises a processor 107 connected to thetransceiver 104 and arranged to control the transceiver 104 and executeprocesses responsive to signals from the transceiver 104 and otherinputs. The processor 107 is also connected to a memory 108, which isarranged to store data related to the delivery of the message from thefirst user 100 to the second user 102.

For example, the memory 108 can store a message 109 intended for thesecond user 102 and an associated destination identifier 110. Thedestination identifier 110 can be any user-readable identifier of thesecond user 102, such as, for example, a device name, a user name, acontact name or a telephone number. Other data stored in the memory 109includes cryptographic keys such as a private key 111 for the firstmobile terminal (labeled Private Key_1) a public key 112 for the firstmobile terminal (labeled Public Key_1), and data regarding other mobileterminals with which the first mobile terminal 101 has been paired (orpreviously communicated with), such as a hardware identity 113 for thesecond mobile terminal 103 (labeled HW_2) and a public key 114 for thesecond mobile terminal (labeled Public Key_2). Further data regardingother mobile terminals can also be stored, but is not shown for clarity.The data stored in the memory is discussed in more detail hereinafterwith reference to FIGS. 2 and 3.

The second mobile terminal 103 has a similar structure to the firstmobile terminal 101. The second mobile terminal 103 comprises atransceiver 115 having the hardware identity 113 (HW_2) and connected toan antenna 116 and a processor 117. The processor 117 is connected to amemory 118 storing data including cryptographic keys such as a privatekey 119 for the second mobile terminal (labeled Private Key_2), thepublic key 114 for the second mobile terminal (Public Key_2), and dataregarding other mobile terminals with which the second mobile terminal101 has been paired (or previously communicated with), such as thehardware identity 105 for the first mobile terminal 101 (HW_1) and thepublic key 112 for the first mobile terminal (Public Key_1). Furtherdata regarding other mobile terminals can also be stored, but is notshown for clarity.

In the example of FIG. 1, only the first user 100 has a message 109 tobe sent, whereas the second user 102 does not have a message stored onthe second mobile terminal 103. In other examples, the second user 102can also have a message to send (e.g. to the first user 100 or anotheruser).

In the example of FIG. 1, the first mobile terminal 101 and secondmobile 103 terminal have previously been “paired”, such that informationregarding each of the first and second mobile terminals has beenexchanged. For example, when first and second mobile terminals arepaired, the hardware identity 105 for the first mobile terminal 101 issent to the second mobile terminal 103 and stored in memory 118, and thehardware identity 113 for the second mobile terminal 103 is sent to thefirst mobile terminal 101 and stored in memory 108. Additionalhigher-level information can also be exchanged between the terminals,such as a device name allocated by the user of the terminal, and thiscan be stored in association with the hardware identity 105. The usercan also make further associations, such as associating the pairedterminal with a contact in the user's address book.

Further optional information can also be shared between the mobileterminals. For example, when the mobile terminals are paired, thecryptographic public key 112 for the first mobile terminal 101 can besent to the second mobile terminal 103 and stored in the memory 118, andthe cryptographic public key 114 for the second mobile terminal 103 canbe sent to the first mobile terminal 101 and stored in the memory 108.

The pairing process can be performed manually by the first and secondusers when the first and second mobile terminals are in wirelesscommunication range of each other, such that the users request a pairingand each enter a mutually agreed shared secret (e.g. a pass-key) intofirst and second mobile terminals. Alternatively, the pairing can beperformed by physically touching the first and second mobile terminalstogether, or bringing them to within a few centimeters range (e.g. ifnear-field communications are used).

Such a pairing process is used for personal area network connections,for example with Bluetooth® transceivers. Note, however, that a pairingprocess in advance is not essential, and that the information regardingeach of the mobile terminals can be obtained from other sources, such asa centralized database.

Reference is now made to FIG. 2, which illustrates a process fordelivering a message based on the proximity between the first and secondmobile terminals of FIG. 1. In this example (as with FIG. 1) the firstuser 100 wishes to send a message to the second user 102.

A first sub-process is a message creation process 200. The messagecreation process 200 is performed when the first user 100 and the firstmobile terminal 101 are located remote from the second user 102 and thesecond mobile terminal 103. In other words, the message creation process200 is performed in advance of the first user 100 being in proximity tothe second user 102. The term “remote” is taken to mean locatedsufficiently far away that the first user 100 would not considerthemselves to be in the presence of the second user 102.

The first user 100 generates 201 a message intended for delivery to thesecond user 102. In one example, the generation of the message can beperformed using only the first mobile terminal 101, for example by thefirst user 100 entering a text message using a keypad of the firstmobile terminal 101, taking a picture using a camera of the first mobileterminal 101, or recording an audio file using a microphone of the firstmobile terminal 101. In an alternative example, the first user cancreate the message using a further user terminal (such as a personalcomputer) and transfer the message to the first mobile terminal 101. Themessage can comprise a document (such as a legal document), one or moreimages, video, audio, text, or any combination of these types of media.

The first mobile terminal 101 receives 202 data comprising the messageas created by the user. If there is a direct generation of the messageon the first mobile terminal 101, then the data comprising the messageis received via an input device on the first mobile terminal 101, e.g.via the keypad, microphone or camera. Alternatively, if the message isgenerated on the further user terminal, then the data comprising themessage can be received at the first mobile terminal 101 via acommunication interface, such as a connection to removable media (e.g. amemory card) or via the transceiver 104.

The data received at the first mobile terminal 101 further comprises adestination identifier for the message (i.e. in this case identifyingthe second user 102). As stated above with reference to FIG. 1, thedestination identifier can be in any suitable form for the first user100 to identify the second user 102, such as a device name, a username,a contact name or a telephone number. The received data comprising themessage is stored 203 in the memory 108 as the message 109 anddestination identifier 110, as shown in FIG. 1. The destinationidentifier 110 is associated to the hardware identifier 113 using theassociations that were established when the mobile terminals werepaired, or by interrogating a centralized database.

The first mobile terminal 101 then starts a sub-process of detecting 204whether it is in proximity to the second mobile terminal 103. The firstmobile terminal 101 uses the transceiver 104 to listen 205 for thepresence of the second mobile terminal 103. This can be achieved inseveral ways. For example, each transceiver (i.e. transceiver 104 and115) can be arranged to periodically broadcast its hardware identity,such that other nearby mobile terminals can discover the presence of thebroadcasting mobile terminal. Alternatively, the first mobile terminal101 can be arranged to periodically transmit request messages using thetransceiver 104, such that nearby mobile terminals receiving the requestmessage respond with their hardware identity, thereby informing thefirst mobile terminal 101 of their presence.

When the first mobile terminal 101 is listening, the first mobileterminal 101 determines 206 whether it is in proximity to the secondmobile terminal 103. This is achieved by the processor 107 at firstmobile terminal 101 comparing any hardware identity received during thelistening process with the hardware identity 113 stored and associatedwith the destination identifier 110 of the message 109.

If the hardware identity 113 is not detected, then the listeningcontinues. If, however, the hardware identity 113 is received, then thefirst mobile terminal 101 determines that it is located in proximity tothe second mobile terminal 103. In this case, the first mobile terminal101 starts an optional authentication 207 sub-process.

The first mobile terminal 101 determines 208 whether to obtain furtherauthentication of the second mobile terminal 103. For some messages, thehardware identity 113 acts as sufficient authentication for the secondmobile terminal 103. However, it is possible for the hardware identity113 to be spoofed, such that a malicious user can receive messagesintended for a different mobile terminal. Therefore, for more sensitiveor important messages, additional authentication of the second mobileterminal 103 can be performed.

The decision of whether to obtain further authentication can be basedupon a user-defined setting that was applied when the message wascreated. Alternatively, the type of message being sent to the secondmobile terminal 103 can be used to determine the authentication levelapplied. For example, simple text messages can be sent without furtherauthentication above the hardware identity 113, whereas the sending of adocument can imply that further authentication of the second mobileterminal 103 is appropriate.

If further authentication is not appropriate, then the message 109 canbe transmitted 209 to the second mobile terminal 103. The transmissionof the message 109 can be performed using the transceiver 104 of thefirst mobile terminal 101 to send the message 109 directly to thetransceiver 115 of the second mobile terminal 103. An alternativetransmission example is illustrated with reference to FIG. 4hereinafter.

On transmission of the message, the first mobile terminal 101 hastherefore automatically detected that it has come into the presence ofanother mobile terminal with which it has a message for delivery, andautomatically delivered the message. Because the first mobile terminal101 has determined that it is in proximity to the second mobile terminal103 before delivering the message, then the benefits of hand-delivery ofthe message are maintained, such as physical, visual confirmation of thereceipt and feedback from the first user 100 seeing the reaction of thesecond user 102.

In some examples, the first mobile terminal 101 can prompt the firstuser 100 to confirm that the message 109 is to be sent, prior to themessage being transmitted 209. This enables the first user 100 toconfirm that he is in the presence of the second user 102, and that themessage can be delivered. Whether or not the user is prompted to confirmthe transmission of the message can be determined by a user-definedsetting applied when the message is created.

Returning to FIG. 2, if the first mobile terminal 101 determines 208that further authentication of the second mobile terminal 103 isappropriate, then an authentication process 210 is performed. Theauthentication process is based on a key exchange technique. Asmentioned above, when the mobile terminals are paired, not only are thehardware identities stored as proxy for the user, but also an exchangeof keys can also be performed. Each mobile terminal has a key pair, andone half of the key pair is exchanged with the other mobile terminal,and stored in association with the hardware identity during pairing.

A simple authentication scheme can then be performed by each of themobile terminals by transmitting back the key that was provided to itduring the pairing process. This key can be matched to the key pair toauthenticate the mobile terminal. For example, if the first mobileterminal 101 has a public key 112 (as shown in FIG. 1) and a private key111, then during pairing the first mobile terminal 101 can provide thepublic key 112 to the second mobile terminal 103. Subsequently, whenpreparing to send a message to the second mobile terminal 103, the firstmobile terminal 101 can request that the second mobile terminal 103 sendback the public key 112 to authenticate the second mobile terminal 103.The first mobile terminal 101 can match the key provided by the secondmobile terminal 103 to the public key 111.

A more secure authentication scheme is shown illustrated in FIG. 3. Inthis case, the key pair at each mobile terminal comprises a public andprivate key. The private key is kept secret, and not distributed fromthe mobile terminal in which it is created. The private key is used toencrypt data. The public key can be freely distributed to other mobileterminals, and can be used to decrypt data encrypted by the private key,but cannot be used to derive the private key. During a pairingoperation, the mobile terminals exchange public keys, and these arestored in association with the hardware identities. For example, afterpairing, the first mobile terminal 101 obtains the public key 114 andhardware identity 113 of the second mobile terminal 103, and the secondmobile terminal 103 obtains the public key 112 and hardware identity 105of the first mobile terminal 101.

When the second mobile terminal 103 receives request for authenticationfrom the first mobile terminal 101, then second mobile terminal firstgenerates 300 an encrypted authentication token. The encryptedauthentication token comprises an encrypted copy of data already knownto the first mobile terminal 101. For example, as shown in FIG. 3, thesecond mobile terminal's own hardware identifier 113 (i.e. from thetransceiver 115) can be read 301 by the second mobile terminal 103 andencrypted 302 using the private key 119 of the second mobile terminal103.

In other examples, different data can be encrypted using the private key119. For example, the hardware identifier 105 of the first mobileterminal 101 can be encrypted, the public key 112 of the first mobileterminal 101 can be encrypted, or a data string provided in the requestfor authentication can be encrypted.

The encrypted authentication token is then transmitted 303 from thesecond mobile terminal 103 and received 304 at the first mobile terminal101. The first mobile terminal then authenticates 305 the token. This isperformed by decrypting 306 the authentication token using the publickey 114 of the second mobile terminal 103 (obtained during the pairingoperation). Note that the public key 114 of the second mobile terminal103 can only decrypt data that was encrypted using the (secret) privatekey 119.

The hardware identity 113 of the second mobile terminal 103 (obtainedduring the pairing operation) is read 307 from the memory 108 and thisis compared 308 to the decrypted authentication token. If the decryptedauthentication token matches the hardware identity 113 of the secondmobile terminal 103, then the authentication is successful 309. This isbecause a malicious user spoofing the hardware identity does not knowthe private key 119, and therefore cannot generate an authenticationtoken that can be decrypted using the public key 114. Alternatively, ifthe decrypted authentication token does not match the hardware identity113 of the second mobile terminal 103, then the authentication is notsuccessful 310.

The same process can also be performed by the second mobile terminal 103to authenticate the first mobile terminal 101 before accepting themessage 109. In this case, the first mobile terminal 101 generates anauthentication token, which is authenticated by the second mobileterminal 103.

Returning again to FIG. 2, following the authentication process 210, thefirst mobile terminal 101 determines 211 whether the authentication ofthe second mobile terminal 103 was successful. If the authentication isnot successful, then the message delivery process is aborted 212 withouttransmitting the message 109. The first user 100 can be prompted toindicate that the message 109 could not be delivered due to insufficientauthentication. If, however, the authentication is successful, then themessage 109 can be transmitted 209 to the second mobile terminal 103, asdescribed above. As stated above, the first user 100 can optionally beprompted to confirm that the message is to be sent, prior to beingtransmitted 209.

The first mobile terminal 101 has therefore automatically detected thatit has come into a co-proximate location with the second mobile terminal103 when a message 109 for the second mobile terminal 103 is waiting tobe delivered, securely authenticated the second mobile terminal 103, andautomatically transmitted the message 109. Because the first mobileterminal 101 has determined that it is in proximity to the second mobileterminal 103 before delivering the message, then the benefits ofhand-delivery of the message are maintained, such as physical, visualconfirmation of the receipt and feedback from the first user 100 seeingthe reaction of the second user 102.

Reference is now made to FIG. 4, which illustrates an alternativeexample of a system for proximity-based mobile message delivery. Thesystem shown in FIG. 4 comprises a first user 100 with a first mobileterminal 101, and a second user 102 with a second mobile terminal 103,as described above with reference to FIG. 1. The structure of the mobileterminals is similar to that described above with reference to FIG. 1 inthat they both comprise transceivers, processors and memory, and storethe same data.

However, in the example of FIG. 4, the transceiver 400 in the firstmobile terminal 101 and the transceiver 401 in the second mobileterminal 103 are not short-range wireless transceivers, but are cellulartransceivers arranged to communicate with one or more base stations 402.The base stations 402 are connected to a communication network 403,which enables the first and second mobile terminals to communicate witheach other. In other examples, the transceivers can be wireless localarea network (WLAN) or wireless wide area network (WWAN) transceiversarranged to communicate with each other via a communication network.

Both the first mobile terminal 101 and second mobile terminal 103further comprise a location sensor, such as a global positioning system(GPS) receiver 404 and 405.

The operation of the system in FIG. 4 is similar to that shown in FIGS.2 and 3. However, the sub-process of detecting 204 whether a mobileterminal is in proximity is not performed using a short-range wirelesstransceiver, but is instead performed using the location sensors. Whenthe first mobile terminal 101 has a message to deliver to the secondmobile terminal 103, the first mobile terminal can periodicallycommunicate with the second mobile terminal using the transceiver 400via the base stations 402 and communication network 403, and requestinformation regarding the second mobile terminal's location. The secondmobile terminal 103 can determine its location using the locationsensors (e.g. GPS receiver 405) and provide the information to the firstmobile terminal 101 via the communication network 403. The first mobileterminal 101 can compare the location of the second mobile terminal 103to its own location determined using GPS receiver 404 to ascertainwhether it is currently in proximity to (i.e. within a predefineddistance of) the second mobile terminal 103.

Alternatively, if for privacy reasons it is not appropriate to transmitthe location of the second mobile terminal 103 to the first mobileterminal 101, then the first mobile terminal 101 can provide itslocation to the second mobile terminal 103, and the second mobileterminal 103 can respond with an indication of whether it is inproximity to the first mobile terminal 101. The indication can be in theform of a distance separating the two mobile terminals, or simply atrue/false response to indicate if they are in proximity.

When it is determined that the first and second mobile terminals are inproximity, then the message is transmitted from the first mobileterminal 101 to the second mobile terminal 103 via the base stations 402and the communication network 403.

FIG. 5 illustrates various components of an exemplary computing-baseddevice 500 which can be implemented as any form of a computing and/orelectronic device, and in which embodiments of proximity-based mobilemessage delivery can be implemented.

The computing-based device 500 comprises one or more inputs 501 whichare of any suitable type for receiving user input. The device alsocomprises communication interface 502 which is suitable for receivinguser data, and transceiver 503 which is suitable for transmitting andreceiving data wirelessly at the computing-based device 500.

Computing-based device 500 also comprises one or more processors 504which can be microprocessors, controllers or any other suitable type ofprocessors for processing computing executable instructions to controlthe operation of the device in order to determine the proximity to otherdevices and transmit messages accordingly. Platform software comprisingan operating system 505 or any other suitable platform software can beprovided at the computing-based device 500 to enable applicationsoftware 506 to be executed on the device.

The computer executable instructions can be provided using anycomputer-readable media, such as memory 507. The memory is of anysuitable type such as random access memory (RAM), a disk storage deviceof any type such as a magnetic or optical storage device, a hard diskdrive, or a CD, DVD or other disc drive. Flash memory, EPROM or EEPROMcan also be used.

An output 508 is also provided such as an audio and/or video output to adisplay system integral with or in communication with thecomputing-based device. The display system can provide a graphical userinterface, or other user interface of any suitable type although this isnot essential.

The term ‘computer’ is used herein to refer to any device withprocessing capability such that it can execute instructions. Thoseskilled in the art will realize that such processing capabilities areincorporated into many different devices and therefore the term‘computer’ includes PCs, servers, mobile telephones, personal digitalassistants and many other devices.

The methods described herein may be performed by software in machinereadable form on a tangible storage medium. The software can be suitablefor execution on a parallel processor or a serial processor such thatthe method steps may be carried out in any suitable order, orsimultaneously.

This acknowledges that software can be a valuable, separately tradablecommodity. It is intended to encompass software, which runs on orcontrols “dumb” or standard hardware, to carry out the desiredfunctions. It is also intended to encompass software which “describes”or defines the configuration of hardware, such as HDL (hardwaredescription language) software, as is used for designing silicon chips,or for configuring universal programmable chips, to carry out desiredfunctions.

Those skilled in the art will realize that storage devices utilized tostore program instructions can be distributed across a network. Forexample, a remote computer may store an example of the process describedas software. A local or terminal computer may access the remote computerand download a part or all of the software to run the program.Alternatively, the local computer may download pieces of the software asneeded, or execute some software instructions at the local terminal andsome at the remote computer (or computer network). Those skilled in theart will also realize that by utilizing conventional techniques known tothose skilled in the art that all, or a portion of the softwareinstructions may be carried out by a dedicated circuit, such as a DSP,programmable logic array, or the like.

Any range or device value given herein may be extended or alteredwithout losing the effect sought, as will be apparent to the skilledperson.

It will be understood that the benefits and advantages described abovemay relate to one embodiment or may relate to several embodiments. Theembodiments are not limited to those that solve any or all of the statedproblems or those that have any or all of the stated benefits andadvantages. It will further be understood that reference to ‘an’ itemrefers to one or more of those items.

The steps of the methods described herein may be carried out in anysuitable order, or simultaneously where appropriate. Additionally,individual blocks may be deleted from any of the methods withoutdeparting from the spirit and scope of the subject matter describedherein. Aspects of any of the examples described above may be combinedwith aspects of any of the other examples described to form furtherexamples without losing the effect sought.

The term ‘comprising’ is used herein to mean including the method blocksor elements identified, but that such blocks or elements do not comprisean exclusive list and a method or apparatus may contain additionalblocks or elements.

It will be understood that the above description of a preferredembodiment is given by way of example only and that variousmodifications may be made by those skilled in the art. The abovespecification, examples and data provide a complete description of thestructure and use of exemplary embodiments of the invention. Althoughvarious embodiments of the invention have been described above with acertain degree of particularity, or with reference to one or moreindividual embodiments, those skilled in the art could make numerousalterations to the disclosed embodiments without departing from thespirit or scope of this invention.

1. A method of transmitting a message from a first user of a firstmobile terminal to a second user of a second mobile terminal,comprising: receiving data at the first mobile terminal when the firstmobile terminal is remote from the second mobile terminal, the datacomprising the message intended for the second user; storing the data atthe first mobile terminal; subsequent to storing the data, the firstmobile terminal detecting that the second mobile terminal is inproximity to the first mobile terminal; and authenticating the secondmobile terminal which comprises receiving a token encrypted using afirst key of a cryptographic key-pair from the second mobile terminal atthe first mobile terminal and decrypting the token using a second key ofthe cryptographic key-pair previously obtained from the second mobileterminal; and transmitting a signal comprising the message from thefirst mobile terminal to the second mobile terminal.
 2. A methodaccording to claim 1, wherein detecting that the second mobile terminalis in proximity to the first mobile terminal comprises receiving anidentity signal transmitted from the second mobile terminal comprisingan identity for the second mobile terminal.
 3. A method according toclaim 2, further comprising determining whether the identity from theidentity signal is sufficient authentication of the second mobileterminal for the message.
 4. A method according to claim 2, wherein thedata further comprises a destination identifier for the message.
 5. Amethod according to claim 4, further comprising determining whether theidentity for the second mobile terminal relates to the destinationidentifier for the message.
 6. A method according to claim 2, furthercomprising pairing the first mobile terminal and the second mobileterminal prior to receiving data at the first mobile terminal, such thatthe identity for the second mobile terminal is provided to and stored atthe first mobile terminal.
 7. A method according to claim 1, whereinreceiving data at the first mobile terminal comprises the first usercreating the message using the first mobile terminal.
 8. A methodaccording to claim 1, wherein receiving data at the first mobileterminal comprises receiving the data from a further user terminal ofthe first user.
 9. A method according to claim 1, wherein the messagecomprises at least one of: a document; an image; a video; audio; andtext.
 10. A method according to claim 1, further comprising promptingthe first user to accept transmission of the message, prior totransmitting the signal.
 11. A mobile terminal, comprising: ashort-range wireless transceiver arranged to detect a further mobileterminal located in proximity with the mobile terminal and output asignal; a memory device including a private encryption key and a publicencryption key that are unique to the mobile terminal; and a processorarranged to encrypt a message stored in memory using the publicencryption key and to receive the signal and, responsive thereto,trigger transmission of the message previously stored in memory to thefurther mobile terminal using the short-range wireless transceiver. 12.A mobile terminal according to claim 11, wherein the short-rangewireless transceiver is a personal area network transceiver.
 13. Amobile terminal according to claim 12, wherein the short-range wirelesstransceiver is a Bluetooth® transceiver.
 14. A mobile terminal accordingto claim 11, wherein the signal comprises an identity of the furthermobile terminal.
 15. A mobile terminal according to claim 14, whereinthe processor is arranged to correlate the identity of the furthermobile terminal from the signal with a destination identifier stored inassociation with the message prior to transmitting the message.
 16. Amobile terminal according to claim 14, wherein the identity of thefurther mobile terminal is a hardware identity associated with thefurther mobile terminal.
 17. A mobile terminal according to claim 14,wherein the identity of the further mobile terminal is a media accesscontrol address.
 18. A method of transmitting a message from a firstuser of a first mobile terminal to a second user of a second mobileterminal, comprising: receiving data at the first mobile terminal whenthe first mobile terminal is remote from the second mobile terminal, thedata comprising the message intended for the second user; storing thedata in a memory at the first mobile terminal; subsequent to storing thedata, the first mobile terminal detecting that the second mobileterminal is in proximity to the first mobile terminal; authenticating atoken received from the second mobile terminal using a uniquecryptographic key assigned only to the second mobile terminal, the tokenbeing previously obtained from the second mobile terminal; andtransmitting a signal comprising the message from the first mobileterminal to the second mobile terminal.